The present invention relates to a modular heat exchanger wherein each of the core modules is formed from a unitary block of extruded heat exchange material and, in particular, to a heat exchanger that provides enhanced beat dissipation and to a method of making the same using an all-welded construction.
Typically, conventional of heat exchangers for use in automobiles utilize heat exchanging core elements which include a series of generally parallel tubular conduits extending between and attached at their opposite ends to inlet and outlet headers. The tubular conduits are provided with heat conducting and dissipating fins which may be either of a flat plate or serpentine construction, and which are soldered or brazed to the tubular conduits. The conduits, in turn, are soldered or brazed to the headers or to similar fluid accumulating tanks.
The rigid soldered or brazed joints have always constituted a common source of heat exchanger failure and, when the heat exchangers are used in automotive applications, usually require removal of the entire radiator for repair, thereby resulting in down time for the automotive equipment. Thus, there has been a long need and desire for both a heat exchanger having unitary core elements and for one in which braised or soldered connections can be minimized and, preferably, eliminated completely.
U.S. Pat. No. 5,303,770 discloses a modular heat exchanger which includes unitary finned tubular core elements which can be assembled into a multi-module heat exchanger, including flow distributing headers or end tanks without brazed, soldered, or welded connections of any kind. The heat exchanger is fully disassemblable in one embodiment, however, mechanical connectors and a substantial number of o-ring seals are required for assembly. In another embodiment, welded or braised connections may be utilized to provide units which are partially disassemblable. However, these units are potentially subject to the prior art problems of inadequate joint strength and environmentally less desirable materials.
U.S. Pat. No. 5,383,517 discloses a modular heat exchanger having unitary finned tubular core elements which can be assembled without any braised, soldered or welded connections or mechanical connectors. The modules are formed from extruded aluminum blocks into which heat exchanging fins are cut or cold formed. Flow accumulating passages are bored into the ends of the modules. The modules are assembled with a high strength adhesive sealant which simultaneously secures the modules together and seals the peripheries of the bore adhesive sealant which simultaneously secures the modules together and seals the peripheries of the bore passages at the module interfaces. However, it has been found during certain applications, increased heat dissipation by the heat exchanging fins is necessary.
It is an object and feature of the present invention to provide a modular heat exchanger with increased heat dissipating ability.
It is a further object and feature of the present invention to provide a modular heat exchanger wherein the modules may be formed from extruded aluminum blocks in to which the heat exchanging fins are cut.
It is a particular object of the present invention to provide such a heat exchanger which utilizes all aluminum components and an all-welded construction.